<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <script src="vue_dev.js"></script>
</head>

<body>
    <div id="app">
        Full Name: {{ fullName }}
    </div>
    <script>
        var app = new Vue({
            el: '#app',
            data: {
                firstName: 'Jack',
                secondName: 'Green'
            },
            computed: {
                fullName: {
                    get: function () {
                        return this.firstName + ' ' + this.secondName;
                    },
                    set: function (newValue) {
                        var names = newValue.split(' ');
                        this.firstName = names[0];
                        this.secondName = names[names.length - 1];
                    }
                }
            }
        })
    </script>
</body>

</html>